To be honest, the lack of sales might be because people aren’t looking for the kind of service you are offering in your gig. I myself, would not want someone else having password access to my Wordpress sites to make changes. Perhaps offering a site review and telling clients how to make the changes would be a better course of action. Customers may not want someone else poking around in their accounts.

Or, it could be that you are not advertising your gig. Never, ever rely upon just the Fiverr marketplace to promote your gigs. ALWAYS promote your gigs off of Fiverr (on your own websites, blogs, printed materials, etc).

You will not be successful on Fiverr unless you take the time to market your gigs.